loophole - an ambiguity (especially one in the text of a law or contract) that makes it possible to evade a difficulty or obligation

amphibology, amphiboly - an ambiguous grammatical construction; e.g., `they are flying planes' can mean either that someone is flying planes or that something is flying planes

parisology - the use of ambiguous words

double entendre - an ambiguity with one interpretation that is indelicate

locution, saying, expression - a word or phrase that particular people use in particular situations; "pardon the expression"

unclearness - incomprehensibility as a result of not being clear

evasiveness, prevarication, equivocation - intentionally vague or ambiguous

lexical ambiguity, polysemy - the ambiguity of an individual word or phrase that can be used (in different contexts) to express two or more different meanings

twilight zone, no man's land - the ambiguous region between two categories or states or conditions (usually containing some features of both); "but there is still a twilight zone, the tantalizing occurrences that are probably noise noise but might possibly be a signal"; "in the twilight zone between humor and vulgarity"; "in that no man's land between negotiation and aggression"